The present invention relates to an intake and exhaust apparatus of a multi-cylinder engine installed in an automobile.
Conventionally, developments of intake and exhaust apparatuses of multi-cylinder engines installed in automobiles have been carried out for the purpose of increasing torque.
For example, JP1992-036023A (the fourth and fifth pages, and FIG. 3) discloses an art for preventing exhaust interference between cylinders by bundling exhaust passages of cylinders that are not continuous in exhausting order, assembling them to be a tapering exhaust pipe, and creating an ejector effect in the narrowed portions of the exhaust passages.
With multi-cylinder engines, in order to increase torque over a wide engine speed range to achieve a wide torque range, it is generally important to suppress the drop of a volumetric efficiency (ηV) over engine speed ranges from a low engine speed range to a high engine speed range as much as possible. Thus, an engine that has no torque shock when accelerating, causes low discomfort, and is excellent in fuel consumption is provided.